Cleaning compositions and methods for removing water insoluble organic materials which employ dibasic ester solvents are known in the art. For example, U.S. Pat. No.'s 4,934,391 and 4,927,556 teaches emulsions of dibasic esters and water, but generally, simple emulsions lack the stability to remain dispersed over long periods of time.
U.S. Pat. No.'s 5,080,831 and 5,080,822 teach true solutions of non-hydrocarbon and non-hydrogenated hydrocarbon organic solvents having water solubilities of from 0.2 to 6% in a combination of water and a solubilizer.
U.S. Pat. No. 5,158,710 teaches a microemulsion of non-hydrocarbon and non-hydrogenated hydrocarbon organic solvents having water solubilities of from 0.2 to 6% with a solubilizing additive, a builder and optionally a coupler. In this patent the builder is a material that enhances the cleaning efficiency of the surfactant by inactivating water hardness, supplying alkalinity to assist in cleaning and buffering the pH of the composition so that it remains above 7.
Other patents relating to emulsions and/or microemulsions include U.S. Pat. No. 5,597,792 which teach an oil continuous microemulsion of water, organic solvents and a surfactant; U.S. Pat. No. 2,606,874 which teaches a hydrocarbon oil emulsion using a C7 or higher alkanediol; and U.S. Pat. No.'s 4,781,848 which teaches hydrocarbon microemulsions for metal roll forming.
Microemulsions have properties that make them attractive for consideration in the formulation of cleaning products. The object of the present invention is to provide a microemulsion characterized in that it has a wide range of compositional and thermal stabilities and that can, without loss of identity as a microemulsion, be combined with solvents and additives for formulation into various cleaning compositions.